Does anyone have a Silicon Solar SunMaXX tank

[Lowhead]

I bought an 80 gallon SunMaXX tank from a Silicon Solar rep here in New England.  I chose it because it is stainless steel and has two heat exchangers.  One is for the solar  hot water panels and and the 2nd HX is to be used with my radiant floor heat.  It also has a port for installing an electric element.  According to the rep they don't document the port for the electric element because it isn't UL listed.  I was disappointed to find out that the port labeled for the electric element is a 3/4 inch.  My 48V heater element (Hotwatt 20-919) won't fit.  I've never seen an electric element that was anything but 1 inch NPT.  In addition, I believe that even though their documentation claims the two HX and water in/out ports are 3/4 NPT they are actually British Parallel Pipe thread (BPPT).  The guy who sold it to me told me to just slobber lots of thread sealant on.  An NPT fitting will bottom out on a flange before seating.  British and national pipe thread have the same thread pitch but differ in the angle and profile of the threads so while they will mate it isn't recommended and I don't think it is safe for a pressure application.  I think Silicon Solar is pulling a fast one by labeling it NPT.  I didn't realize until after I bought it that it is made in China.  I'm pretty discouraged and of course they are closed today (MLK day).  I can buy a BPT to NPT adapter at www.mcmaster.com so I can live with that but the main reason for choosing this tank was because of the electric element port.  That was to be my dump load for my 900 watt hydro.  So far I can't find an element to fit and I'm probably going to have to get one custom made.  If anyone knows of someone who makes a stainless tank that has two HX's and an electric element port, I'll return or sell this one.  So far I've looked at Viessman, Stiebel, SuperStor and a few others with no results.  I don't want a glass tank unless I have to.

Thanks

LowHead

[Jon Miller]

If it where me I would take it back, im sure it wasnt cheap.  Then find a local company who can make one for you.

Or at the very least get them to pay for an adapter.

[pepa]

hi lowhead,is there a way to drill out and tap the hole to i"? pepa

[halfcrazy]

or could you use a short 3/4 nipple and then a 3/4 to 1 inch adapter? would the heater fit thru a 3/4 nipple?.

[Lowhead]

There isn't enough material there.  If I drilled it out I'd have to weld on a new flange fitting.  I suppose I could do that but I would have safety concerns and it would certainly void the warranty.  

I just talked to Watlow about a custom heater element.  With a bit of parts bin engineering I can order a 900 watt 57 volt, 12 inch long Inconel element silver soldered onto a 3/4 NPT fitting.  I'm waiting for the quote to come back but I expect it will be about $150.  I'll have to order it through my company as an engineering sample.

LowHead

[Lowhead]

The heater elements won't fit through the 3/4 NPT port.  It is actually two elements that you can jumper to be 24/48 volts.

[halfcrazy]

well that sucks i would try to make them pay for the custom element and the adapters though.

[dnix71]

The twin heat exchanger 80 gallon SunMaxx's 'retail list' for $2,600. Take it back and get something properly engineered.

That's an obscene amount of money to pay for something not designed correctly.

[electrak]

Are you using an inverter? McMaster carr has 3/4" 120volt 1000watt  heater cat# 4654T13  $117.03  

I agree with them, take it back, or get them to pay for the adaptors, stainless BPPT-NPT can get pricy. I just bought some.

[Lowhead]

So here is my update.  Watlow came up with a custom element.  $103 is a great deal for a custom made element considering I paid about $90 for the one that won't fit.  It will take a couple of weeks.  I didn't get around to calling Silicon Solar today to complain about the fittings.  I bought the tank from a guy in Maine who's wife is a local rep for them.  He had 5 left over from an industrial job and is selling them on Craigslist for $1450 new in the box with full warranty so I got a good deal for a stainless tank.  They don't advertise the heater port as a feature so I can't really complain about that being undersized.  I think the BPPT mislabeled as NPT is a legitimate safety issue.  If I have to buy 6 adapters from Mcmaster for $7 I still got a good deal.

Low Head

[cmatheson]

Hello Low Head

First, along with the element that you purchased did you happen to get a thermostat that actually has a temp probe to be inserted in the space on the SunMaxx tank in the element position? The only kind I can find are the typical tank mount kind. The problem is that the SunMaxx tank doesn't have space for the thermostat mounting. Second, what was the part number of those NPT-BPPT threading adapters that you got from McMaster-Carr. I want to be sure I am getting the right components.

Any help would be greatly appreciated!